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Onkyo Integra A-819GT (hot heatsink)

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Ahahaaha I just posted about how every single onkyo I have ever seen runs HOT.

I'd give it a lot of space - away from your vinyl collection ;)

*EDIT* 1981 was a fine year, BTW. Welcome to AK! *EDIT*
 
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Actually, I don't recall that it should be hot with no signal. They have always run hot IIRC, but I can't say I have ever measured without any input or output. Why would you have it in a state with no speaker connected and no input source?
 
Class B. How hot is hot? The function of a heatsink is to pull the heat away from the output devices,so.Yes heatsinks will get warm to the touch.
 
You should be able to rest your hand on the heatsink without being uncomfortable. If not, adjust the idle current per the service manual.
 
I observed the heat is still there even when not in used for 4 hrs no signal, I forgot to turn it off.

So the next day, I disconnected all connections except the AC power. I turned it on, aftr 30 mins the heatsink is hot. Hotness is like its been used at full power.

I know something is wrong (but not so sure), yes, there maybe problems with the idle current but unfortunately I cant find a service manual for this model.

I have pictures of it. there is only 1 trimmer on the driver on each amp. I can see 3 test points near the fuses but which is which... do u have service manual for this model?, thanks..





pcbcomponentside.jpg


pcbsolderside.jpg
 
See the white ceramic resistors near the power transistors? Measure the voltage drop across the leads of one of them in each channel. I can't find the service manual but 40mA is a good value to use. Multiply .040 x the resistor value to get the voltage to adjust to. Adjust with no input and no load, Monitor for 5 minutes and re-adjust. Keep monitoring the voltage until it is stable, re-adjusting as necessary. Since both channels are mounted on the same heatsink, the heat from one will affect the other, so go from one channel to the other and do the adjustment. Get mini clip leads for your meter if you don't have them.
http://www.mcmelectronics.com/product/POMONA-3782-36-0-/201-015
http://www.mcmelectronics.com/product/POMONA-3782-36-2-/201-016
 
Well going off the idea that it's like their Integra M series amps...same set up...you hook up a meter to the two outside pins and adjust that trim pot to 15mv.....once again don't know if yours is the same but it appears to be the same exact set up like the Integra M-504 and M-508 amps.
 
all ok (Moderator pls delete this post)

bias voltage are normal.... everything is normal. The heat I felt is not generated only by the output transistors heat sinks, there are others that are contributing such as the pre-driver transistors and on the right that are mounted on smaller heat sink, probably these are regulator. Everything is Normal! thanks for your support.
 
I lied and I need HELP!

Upon closer inspections, there are several pairs (left and right) of darkened resistors, slightly burned, cant read the codes. These are located near the servo unit with plastic exclosure.. Im sure these something to do with the excess heat generated by the drivers. Probably their biases are not right.
Strange.. the sound is like it has no problem at all, except for that heat.

Service manual is hard to find, do you have service manual of a unit with DC super servo drive? Not necessarily similar to this model. I just want to study how it works so I can trouble shoot mine.

Please share me you manual, any model with this Super Servo feature...
 
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